Electrolytic cells



April 24, 1956 R. Q. BOYER ELECTROLYTIC CELLS Filed April 21, 1944 3Sheets-Sheet 1 4 INVENTOR. Poberf Q. Boyer @441 4 M ATTORNEY.

April 24, 1956 R. Q. BOYER ELECTROLYTIC CELLS '3 Sheets-Sheet 3 FiledApril 21, 1944 HH I11 E m9 owl g 2 mm m: g ms 5 m: a: L Q ma 1 m9 m9 hMQ INVENTOR. Robsrf' Q. Boyer Ma W- ATTORNEY.

United States atent ELECTROLYTIC cums Robert Q. Boyer, Berkeley, Calif.,assignor to the United States of America as represented by the UnitedStates Atomic Energy Commission Application April 21, 1944, Serial No.532,162 3 Claims. or. 204-215 The present invention relates toelectrolytic cells and more particularly to improved electrolytic cellsthat are especially adapted for use in conjunction with the reductionand purification of wash solutions derived from calutrons employed inthe calutron method of producing uranium enriched with U In thecopending application of Ernest 0. Lawrence, Serial No. 557,784, filedOctober 9, 1944, and now Patent No. 2,709,222 granted May 24, 1955,there is disclosed a calutron, a machine designed to separate theconstituent isotopes of an element and more particularly to increase theproportion of a selected isotope in an element containing severalisotopes, in order to produce the element enriched with the selectedisotope. More specifically, the calutron mentioned is especiallydesigned to produce uranium enriched with the thermal-neutronfissionable isotope U In the copending application of James M. Carterand Martin D. Kamen, Serial No. 532,159, filed April 21, 1944, there isdisclosed an improved process of producing uranium enriched with Uemploying the calutron method and comprising first-stage andsecond-stage calutrons. In accordance with this process, uranium ofnatural or normal isotopic composition is treated in a firststagecalutron in order to produce as a product uranium singly enriched with Uwhich uranium singly enriched with U is treated in a second-stagecalutron in order to produce as a product uranium doubly enriched with Uwhich uranium doubly enriched with U may be used commercially. In theoperation of either a firststage calutron or a second-stage calutron,the compound U014 is treated, whereby a residue of the UCL; is depositedon the parts of the calutron disposed in the source region thereof,metallic uranium enriched with U is deposited in the first pocket of thecollector of the calutron, and metallic uranium impoverished withrespect to U is deposited in the second pocket of the collector of thecalutron. Further, the difierent deposits of UCli are separatelyrecovered by a water wash step; the different deposits of metallicuranium are separately recovered by an acid wash step; three compositesolutions are produced of the separate washes in accordance with theirisotopic composition; and the three composite solutions are separatelypurified to produce first, second and third separate batches of astandard compound of uranium. The first, second and third batches ofthis uranium compound respectively comprise uranium of natural or normalcomposition with respect to U uranium singly enriched with U and uraniumdoubly enriched with U The first and second batches of the uraniumcompound are then converted back to UCla. for re-treatment in thefirst-stage and second-stage calutrons, respectively; while the thirdbatch of the uranium compound is available for commercial use.

In the copending application of Martin D. Kamen and Abel De Haan, SerialNo. 542,378, filed June 27, 1944, there is disclosed an improved processof purifying a composite solution of the character mentioned in order toseparate uranium from metal impurities in the solution. In accordancewith this process, a composite solution comprising UO2++, Cu++, Ni Fe+++and Cr+++ ions is first acidified with HCl and then reducedelectrolytically, whereby the uranyl ion, UOz++, and the ferric ion,Fe+++, are respectively reduced to the uranous ion, U++++, and theferrous ion, Fe++. Thus the reduced solution contains U++++, Cu++, Ni++,Fe++ and Cr+++ ions. To the reduced solution there is added oxalic acid,whereby the uranium is precipitated as U(CzO4)z-6H2O away from the metalimpurities in the solution. The solution is then filtered in order toobtain the uranous oxalate precipitate, leaving the metal ions mentionedin the filtrate; which standard compound of uranium is subjected tofurther treatment or is available for commercial use, as previouslyexplained.

Accordingly, it is an object of the invention to provide an improvedelectrolytic cell that is especially designed to reduce a wash solutionof the character and composition mentioned, whereby uranyl and ferricions are respectively reduced to uranous and ferrous ions.

Another object of the invention is to provide an electrolytic cell ofimproved construction and arrangement, that is compact and efiicient inoperation.

Another object of the invention is to provide in an electrolytic cellimproved cathode structure, that is arranged to sustain efiiciencyduring continuous operation of the cell.

The invention both as to its organization and method of operationtogether with further objects and advantages thereof, will best beunderstood by reference to the following specification taken inconnection with the accompanying drawings in which Figure 1 is afragmentary plan view of an electrolytic cell embodying the presentinvention; Fig. 2 is a fragmentary longitudinal sectional view of theelectrolytic cell taken along the line 2-2 in Fig. 1; Fig. 3 is atransverse sectional view of the electrolytic cell taken along the line33 in Fig. 2; Fig. 4 is a transverse sectional view of the electrolyticcell taken along the line 44 in Fig. 2; and Fig. 5 is a diagrammaticillustration of a solution treatment system in which the electrolyticcell is incorporated.

Referring now more particularly to Figs. 1 to 4, inclusive, of thedrawings, there is illustrated an electrolytic cell 10 that embodies thefeatures of the present invention and comprises a lower casing section11 and an upper casing section 12. The lower casing section 11 issubstantially rectangular in plan, including a flat bottom wall 13,upstanding side walls 14 and upstanding end walls 15, secured togetherin liquid-tight relation, the

"perimeter of the bottom wall 13 being received in interior groovesformed in the side walls 14 and in the end walls 15 adjacent the loweredges thereof. Further, the lower casing section 11 includes arectangular outwardly extending flange 16 disposed about the upper openend thereof and rigidly secured to the adjacent outer surfaces of theside walls 14 and the end walls 15. Similarly, the upper casing section32 is substantially rectangular in plan, including a fiat bottom Wall17, upstanding side walls 18 and upstanding end walls 19, securedtogether in liquid-tight relation, the lower edges of the side walls 18and the end walls 19 being received in a rectangular groove formed inthe upper surface of the bottom wall 17, and disposed inwardly from theperimeter thereof. Accordingly, the bottom wall 1.7 of the upper casingsection 12 extends outwardly from the side walls 18 and the end walls 19in order to define in effect a rectangular outwardly extending flange20, disposed about the lower closed end of the upper casing section 12.Preferably,

the parts of the lower casing section 11 and the upper ej ienzs beingcongruent. Also, a sealing gasket 21, formed of rubber or the like, isarranged between the lower surface.

of the bottom wall 17 and the upper edge of the side walls .14 and theend walls 15, and extending between the flanges 20 and 16. Finally, theflanges Hand 20 are removably secured together in liquid-tight relationby a series .of bolts 22, extending through aligned openingsformedltherein, the ends'of the bolts 22 receiving nuts. 23. Washers 24and 25 surround the shanks of. the bolts 22 andare respectively disposedbetween the heads of the .bolts 22 and the uppersurfaee of the flange20, andv between the nuts 23 and the lower surface of the flange 16,Further, a drain pipe. 26 .is threaded in an opening formed inthe bottomwall 13 adjacent the left-hand end wall 15,; which drain pipecommunicates with the interior of the lower casing section 11. The endof the. drain pipe 26. terminates in a petcock 27, whereby the drainpipe 26 may beselectively opened or closed.

Av number of laterally extending and longitudinally spaced apart slots17a are provided through the bottom wall 17 within the area bounded'bythe side walls 18 and theend walls 19; and a correspondingplurality ofup:

standing laterally extending and longitudinally spaced.

apart pairs of partition elements 28 are carried by the upper surface ofthe bottom wall 17, the individual partition elements 28 ofv each pairbeing disposed on the opposite side of a slot 17a. More particularly,each upstanding partition element 28 is retained in place by a pair ofaligned upstanding slotslSa, formed in the inner surfaces of the sidewalls,18, and an aligned laterally extendingrecess 17b, formed in theupper surface of .the bottom wall 17 adjacent a slot 1711. Thus, eachpartition element 28 is retained in placein upstanding position by asubstantially U-shaped composite groove comprising a pair of upstandingslots 18a formed in the inner surfaces of the side walls 18 and acooperating laterally extending recess 17b formed in the upper surfaceof the bottom wall 17. Finally,: an upstanding laterally extendingpartitionfelemen t 29 is carried .by the upper'surface of the bottomwall 17, the partition element 29. beingspaced longitudinally and to theright-hand side of the partition element 28 disposed most remote fromthe left-hand end wall 19. Also, the upstanding partition element 29 isretained in place by a pair of upstanding cooperating slots formedin theinner surfaces of the side walls 18 and an aligned laterally extendingrecess formed in the upper surface of the bottom wall 17, in a manneridentical to that previously explained in conjunction with eachpartition element 28.

The various partition elements 28 and the partition element 29 compriserectangular plates formed of a porous semipermeable insulating materialof the ceramic type, such as alundum or sintered Pyrex glass.Collectively, the pairs of partition elements 28 and the partitionelement 29 constitute partition structure defining a plurality ofinterposed anode and cathode compartments 30 and 31, respectively, inthe upper casing section 12. More particularly, the two partitionelements 28 of each pair cooperate with each other and with the portionsof the side walls 18 disposed therebetween to define a cathodecompartment 31 having an open lower end formed by a cooperating slot17a. Similarly, each left-hand partition element 28 of a pair cooperateswith the adjacent righthand partition element 28 of a pair and with theportions of the side walls 18 and the bottom wall 17,, disposedtherebetween to define an anode compartment 30 having a closed lowerend. Further, the left-handpartition element 28 of the pair disposedadjacent theleft-hand end wall 19 cooperates therewith and with theportions of the side walls 18 and the bottom wall 17disposedtherebetween to define the anode compartment 30 disposedimmediately,adjacent..the..left:l1and end .wall.19.i Finally,.

the right-hand partition element 28 of the pair disposed adjacent thepartition element 29 cooperates therewith and with the portions of theside walls 18 and the bottom wall 17 disposed therebetween to define theanode compartment disposed most remote from the left-hand end wall19. pU H v The upper edges ofthevarious pairs of partition elements 28 andthe partition element 29. aredisposed substan'tially flush with theupperedges of the side walls 18,

and the upper edges of the side walls 18 are substantially flush withthe upper edges of the end walls 19; whereby the upper edge of the uppercasing section 12 is substantially flat and parallel to the bottom wall13 of the lower casing section 11. Further, a pair of conductors in theform of busbars 32, formed of copper or the like, are secured to theupper edges of the side walls 18 by a number of screws 33. The left-handends of the 'busb'ars 32 are secured togetheryby a conducting strap 34by screws 35; and a conducting terminal 36 is secured to the mid-portionof the strap 34 by a screw 37. A plurality of anode elements 38 iscarried by the busbars 32 and arranged in the respective anodecompartments 30. Each of the anode elements 38 comprises a substantiallyrectangular plate provided at its upper end with laterally andoppositely extending lugs 38a which overhang the respective; b usbars32. The anode elements 38 are formed of a conducting material resistantto chlorine and hydrochloric acid solutions, such as graphite, and areelectrically connected to the busbars 32 by terminal structure includingscrews 39 and flexible conductors 40. More particularlyythe flexibleconductors 40 are of the braid or pigtail type, one end of each pigtail40 being brazed or soldered to the adjacent busbar 32, and the other endof the pigtail'40 being provided with an eyelet through which theassociated screw 39 extends, the

screw 39 extending through the adjacent lug 38a formed onthe'cooperating anode element 38. Thus, the terminal 36 isconnected bylow resistance paths to each of the anode elements 38 in multiple,whereby collectively the anode elements 38 constitute an anode. I

A longitudinally extending shaft 41 is rotatably mounted in twobearingbrackets .42 and 43, secured to the lower surface of the bottomwall 17 by screws 44 and 45, respectively. The bearing brackets 42 and43 I are aligned"substantially along the longitudinal centerline ofthebottom wall 17 and consequently of the electrolytic cell 10,-thebearing bracket 42 being disposed adjacent the vleft-h'and'end 'wall 15,and the bearing bracket 43 being disposed. remotev from the-left-handend wall 15 and spaced someldistancefrom. the right-hand end wall 15.The vbearingbrackets42 and 43 may suitably comprise complementarysections formed of stainless steel and securedtogether and to .thebottom wall 17 by the screws 44 and 45, 'as-previouslynoted. The shaft41 carries a plurality ofv longitudinally spaced apart cathode members46in the form of .disks. Each of the cathode members 46 isrigidly.securedv to the shaft 41, so that it is rotatable therewith, and extendsdownwardly into the lower casing. section .11. and;.upw-ardly. through acooperating one of the slotsp17a intoav cooperating one of .the cath-,

and a bevel gear 47 is rigidly secured to the right-hand.

e the sha t. 41, wh re yt enn por i n of th bevel gear 47 extendsupwardly through. the opening 17c into the;. upper casingsection 1 2,and the lower. portion of the bevel gear 47 extends downwardly into thelower casing section 11. More particularly, the bevel gear 47 isprovided with a collar 48 which is secured to the righthand end of theshaft 41 by a setscrew 49 and carries a flange 50 engaging theright-hand side of the bearing bracket 43 to provide a thrust bearingfor the shaft 41.

The bevel gear 47 meshes with a bevel gear 51 rigidly secured to anupstanding operating shaft 52 adjacent the lower end thereof. Theextreme lower end of the operating shaft 52 is supported in a thrustbearing 53 carried by a bearing bracket 54; and the upper end of theoperating shaft 52 is supported by a guide bearing 55 carried by abearing strap 56. More particularly, the bearing bracket 54 comprisestwo laterally upwardly and outwardly extending legs 57, which aresecured by screws 58 to the lower surface of the bottom wall 17, and alongitudinally upwardly and outwardly extending leg 59, which is securedby the screw 45 to the bearing bracket 43. The thrust bearing 53comprises a threaded step 60 accommodating adjustment of the operatingshaft 52 in the vertical direction, and consequently proper mesh betweenthe bevel gear 51 carried thereby and the bevel gear 47 carried by theshaft 41. The bearing strip 56 extends laterally -across the uppercasing section 12, and the opposite ends thereof are suitably anchoredto the upper edges of theside walls 18 by screws 61.

A pool of mercury 62 is arranged in the lower casing section 11, themass of the mercury pool being such that columns of mercury rise in theslots 17a into the cathode compartments 31. Preferably, the columns ofmercury rise into the cathode compartments 31 a slight distance abovethe upper surface of the bottom wall 17, whereby the shaft 41 and thelower segments of the cathode members 46 are immersed in the mercurypool 62. An upstanding cathode plate 63 extends through the upper casingsection 12 downwardly through the opening 17c and terminates in thelower casing section 11, whereby the lower end of the cathode plate 63is immersed in the mercury pool 62. A substantially U-shaped clip 64 isrigidly secured to the cathode plate 63 and is adapted to overhang theadjacent upper edge of the right-hand end wall 19, thereby securely toretain the cathode plate 63 in position.

Further, a body of electrolyte 65 is arranged in the upper casingsection 12 as a head upon the mercury pool 62, the body of electrolyte65 filling the various anode and cathode compartments 30 31,respectively, andelectrically communicating through the porous partitionstructure including the partition elements 28 and 29, the mass of thebody of electrolyte 65 being such that the upper segments of the cathodemembers 46 are completely immersed therein. The cathode compartments 31in the upper casing section 12 are arranged in groups, each groupcontaining several adjacent individual cathode compartments, theindividual cathode compartments in each group being connected in seriesrelation by a conduit system, and the different groups of cathodecompartments being connected in parallel relation by the conduit system.

Considering now the illustrated embodiment of the electrolytic cell ingreater detail, the partition structure comprises nine pairs ofpartition elements 28, whereby nine individual cathode compartments 31are formed in the upper casing section 12 and arranged in longitudinallyspaced apart relation, each of the cathode compartments 31 communicatingthrough the associated slot 17a with the lower casing section 11. Also,the rotatably mounted shaft 41 carries nine longitudinally spaced apartcathode members 46 which extend through the respective slots 17a intothe respective cathode compartments 31. Further, the partition structurecomprising the nine pairs of partition elements 28 and the partitionelement 29 forms ten individual anode compartments 30 in the uppercasing section 12, arranged in longitudinally spaced apart relation andin interposed relation with respect to the cathode compartments 31.Thus, in the partition structure and anode compartment 30 is positionedon either side of each cathode compartment 31. The nine cathodecompartments 31 are arranged in three groups of three individual cathodecompartments each; the three groups of cathode compartments 31 areconnected in multiple by the conduit system mentioned; and the threeindividual cathode compartments 31 in each group are connected in seriesby the conduit system mentioned. 7

Referring now more particularly to Figs. 1, 2 and 5, the conduit systemmentioned comprises three inlet pipes 101, respectively serving thethree groups of cathode compartments 31 and respectively communicatingwith the first, fourth and seventh individual cathode compartments 31;positioned from the top of the electrolytic cell 10 toward the bottomthereof, as viewed in Fig. 5, and from the right-hand side of theelectrolytic cell 10 toward the lefthand side thereof, as viewed inFig. 1. Also, the conduit system mentioned comprises three outlet pipes102, respectively serving the three groups of cathode compartments 31and respectively communicating with the third, sixth and ninthindividual cathode compartments 31. The adjacent right-hand ends of thefirst and intermediate individual cathode compartments 31 in each groupare connected together by U-shaped header pipes 103, the adjacentright-hand ends of the first, second and fourth, fifth and seventh,eighth individual cathode compartments 31 in the electrolytic cell 10being so connected by the header pipes 103. The adjacent left-hand endsof the intermediate and last cathode compartments 31 in each group areconnected together by U-shaped header pipes 104, the adjacent left-handends of the second, third and fifth, sixth and eighth, ninth individualcathode compartments 31 in the electrolytic cell 10 being so connectedby the header pipes 104. In conjunction with the conduit system, it isnoted that a series of aligned openings 18 are formed in the side walls18 and communicate with the cathode comparaments 31 in order to receivethe various pipes 101, 102, 103 and 104, the openings 18b being disposedabove the cathode members 46 so that the upper segments of the cathodemembers are completely immersed in the body of electrolyte 65.

Accordingly, it will be understood that a first stream of electrolytemay be conducted from a first of the inlet pipes 101 through the firstcathode compartment, via a first of the header pipes 103, through thesecond cathode compartment, via a first of the header pipes 104, andthrough the third cathode compartment to a first of the outlet pipes102. Similarly, a second stream of electrolyte may be conducted from asecond of the inlet pipes 101 through the fourth cathode compartment,via a second of the header pipes 103, through the fifth cathodecompartment, via a second of the header pipes 104, and through the sixthcathode compartment to a second of the outlet pipes 102. Finally, athird stream of electrolyte may be conducted from a third of the inletpipes 101 through the seventh cathode compartment, via a third of theheader pipes 103, through the eighth cathode compartment, via a third ofthe header pipes 104, .and through the ninth cathode compartment to athird of the outlet pipes 102. Thus, the conduit system connects theindividual cathode compartments 31 in the electrolytic cell 10 inparallel series relation.

Considering now the arrangement of the solution treatment system ingreater detail, reference is made to Fig. 5. The operating shaft 52 issuitably connected to a motor 105, which is preferably of the electrictype; the cathode plate 63 is connected to the negative terminal of asource of direct current supply; and the terminal 36 is connected to thepositive terminal of the source of direct current supply. Thus, when themotor 105 is operated, the operating shaft 52 is rotated, causing thebevel gear 51 to drlve the bevel gear 47 in order to rotate the shaft41. As the shaft 41 is rotated, the cathode members 46 are rotated,whereby repeatedly the lower segment of each of the cathode members ordisks 46 is removed from the mercury sagas theassoelate fftli'e"'athodefcomp'aitm theupper'sgment thereof I is'removedfrom the body ofelectrolyte 65 in'itheasso'ci'ated one'of the cathodecornpartment'sf31iand'immer'sed in themercury pool 62. The motor 105Qisiop'eratedat a suitable speed in view of the gearreduction'ratiobetween the bevel g'ear'51'and the bevel gear 47, so thatthe shaft 41 and consequently the disks 46 rotate at the required speed,as explained more fully hereinafter. I v v I w Each of 'th'e'inlet pipes101 terminates in a funnel 1.06; and'each .of the outletpipes 1 02terminates in' an outlet header'107. Also, the conduit system comprisesan inlet header 108 provided with three branches 109, which rspectivelyfeed the three funnels 106 respectively termihating the threeinlet pipes 101. More particularly, each of the branches 109 is providedwith an adjustable petcock 1 10, whereby th'e'flow of electrolytetherefrom into the associated funnel106 may be selectively controlled.Finally, the conduit system comprises a supply receptacle 111, a storagereceptacle 112, a'pressure regulator 113,

and a pressure conduit 114. One end of the pressure conduit114 isconnected to a source of air under pressure, not shown; and the otherend of the pressure conduit 114 terminates in the supply receptacle 111.Also, the mid-section of the pressure conduit 114 is connected to anupstanding tube 115 extending into the pressure regulator 113. Moreparticularly, the pressure regulator 113 comprises a vessel 116containing a column of mercury 117, into which the upstanding tube 115extends, the lower end of the upstanding tube 115 being submerged therequireddepth in the column of mercury 117 in order to establish. acorresponding pre-determinedv blow;out pressure in the vessel 116. Theupper end of the vessel 116, is closed by a stopper 118, through'which avent pipe 119extends. It will be understood that the pressure regulator113 maintains the previously mentioned pressure in the end of thepressure conduit 114 extending into. the supply receptacle 111. In theevent the pressure in the pressure conduit 114 exceeds the predeterminedpressure mentioned, ,air is blown through the upstanding tube 115against the pre-determined column of mercury 117 into the upper portionof the vessel 116, and vented to the atmosphere via the vent pipe119,'whereby the air pressure in the pressure conduit 114 is maintainedat the required value.

The supply receptacle 111 is in the form of a bottle, the throat ofwhich is closed by a stopper 120 through which the pressure conduit 114extends, the lower end of the pressure conduit 114terminating adjacentthe top of the 7 supply receptacle .111. Also, the supply receptacle 111contains aquantity of electrolyte 121 which is to be conducted throughthe electrolytic cell to the storage 'receptacle 112. A conduit 122extends through the stopper120and connects the supply receptacle 111 tothe inlet" header 108, one end of the conduit 122 being connected to theinlet header 108 and the other end of the conduit 122 terminating in thesupply receptacle 111 adjacent the bottom thereof. Finally, the outletheader 1.07 is connected by a conduit 123 to the storage receptacle 112,one end of the conduit 123 being connected to the outlet header 107 andthe other end of the conduit 123 terminating in the storage receptacle112adjacent the top thereof. The storage receptacle 112 is, in the formof a bottle, the throat of which is closed by a stopper 124 throughwhichthe conduit 123 extends. Also, a vent pipe 125 extends through thestopper 124; andthe storage receptacle 112 is adapted. to receive andstore a quantity of electrolyte 126 which has been conductedthroughtheelectrolytic cell 10. v H V,

Considering now the flow of the electrolyte in the conduit systemthrough .the electrolytic cell 10, it will be understood thatapre-determinejd.regulated pressure is maintained .by .the pressureregulator'113 inth'e pressure conduit 114, whereby the regulatedpressure is main- 8? tainediin ejuppfpo'rtion of the supply receptacle"1-11. Thejpressurejmaintainedin the'upper portion ofthe' supplyreceptacle 111 as a head over the quantity of electrolyte 121 therein,forces the electrolyte through the conduit 122 into the inlet header108, and consequently into the three branches 109. 'The petcocks 110 areappropriatelyadjusted, whereby three streams of electrolyte aredelivered into the three associated funnels 106, causing the requiredstatic head of electrolyte to be maintained in the three inlet pipes101. The electrolyte flows from the three inlet pipes 101 through thethree groups of cathode compartments 31, in parallel series relation in'the electrolytic cell 10, into the outlet pipes 102, in the mannerpreviously explained. The electrolyte then flows from the outlet pipes102 into the outlet header 107, and therefrom through theconduit 123into the storage receptacle 112. As the electrolyte 126 is deliveredto'the storage receptacle 112, air therein is vented through the vent.pipe 125 to the atmosphere.

Considering now the construction and arrangement of the componentelements of the electrolytic cell 10 in greater detail, reference isagain made to Figs. 1 to 4, inclusive, and it is noted that in thespecific embodiment of the electrolytic cell 10 illustrated, each of thedisks 46 has a diameter approximately 12 cm. and approximately and ofits area are respectively immersed in the body of electrolyte and in themercury pool 62. Thus, about cm. of the area 'of each of the disks 46 isimmersed in the body of electrolyte 65, whereby the total area of thecathode immersed in the body of electrolyte 65 is approximately 720 cm.Employing an electrolyte constituting a hydrochloric acid solution,electrolytic currents within the range to amperes have been obtained,whereby the electrolytic current was approximately 0.2 ampere per cm. ofarea of the cathode, which value is wellwithin the usual operatinglimits, 0.1 to 0.3 ampere per cm. at the cathode, for electrolyticcells. The electrolytic current mentioned was obtained when severalvolts, about four, direct current was applied between the cathode plate63 and the anode terminal 36. Under the operating conditions mentioned,it was found that three streams of electrolyte conducted through thethree groups of cathode compartments 31 of reasonable volume permittedoperation without undue heating of either the electrolytic cell 10 orthe electrolyte. More particularly, each of the three streams ofelectrolyte comprised a flow of approximately 50 cc. per minute, thetemperature rise of the electrolyte being of the order of 55 C.Specifically, 150 cc. of electrolyte per minute were conducted throughthe cell, experiencing a temperature rise from l5 20 C. to 70-75 C. Whenthe electrolyte was conducted through the electrolytic cell 10 at therate and under the operating conditions mentioned, there, was no undueheating of the component parts of the electrolytic cell. a

Now considering the operation of the electrolytic cell 10 in conjunctionwith the solution treatment system, it is noted that the; anode andcathode compartments 30 and 31 are initially filled'with a body ofelectrolyte 65 comprising about 3N HQ; then the solution to be treatedis conductedfrom thesupply receptacle 111 through the. cathodecompartments 31 operating under the conditions specified; whereby theinitial body of electrolyte 65 in the cathode compartments 31 is atleast partially displaced bythe solution which then becomes part of theelectrolyte in the cathode compartments 31. Specifically, the solutionwhich is conducted from the supply receptacle 111 is about 3N HCl andcontains UO2++, Fe+++, Cu++, Ni++ and Cr+++ ions. This hydrochloric acidsolution is prepared in the'mann'er disclosed in the previouslymentioned copending application of Kamen'and de aa which acid solutioncomprises a wash solution produced in the manner disclosed in thepreviously mentioned, 'co'pending application of Carter and Kamen; whichwash solution is derived from a calutr'on' of the r character of thatdisclosed in the previously mentioned application of Lawrence.

The solution is reduced in the electrolytic cell 10 and is conductedinto the storage receptacle 112, the solution conducted into the storagereceptacle 112 comprising U++++, Cu++, Ni++, Fe' and Cr+++ ions. Moreparticularly, the established rate of flow of the solution through theelectrolytic cell 10, under the operating conditions specified, is suchthat the uranyl ion, UO2++, and the ferric ion, Fe.+++, are respectivelyreduced by the electrolyticicurrent to the uranous ion, N++++, and theferrous ion, Fe++. Of course it will be understood that a small amountof the ions Cu Ni++, Fe and Cr are completely reduced to the metalstates Cu", Ni Fe and Cr by the electrolytic current, which metalimpurities in the body of electrolyte 65 are carried by the rotatingdisks 46 into the mercury pool 62. It will be understood that bysuitably altering the operating conditions, such as by reducing the rateof flow of electrolyte through the cell and/or by increasing the currentdensity, the reduction of ions other than U++++ to the metal state maybe made substantially complete, if desired. The metal impurities carriedinto the mercury pool 62 by the rotating disks 46 are either trappedtherein or amalgamated therewith, whereby the body of electrolyte 65 iskept free of metal impurities liberated therein incident to theelectrolysis. Specifically, the copper, chromium and nickel impuritiesreadily amalgamate with the mercury pool 62, whereas the iron impurityis trapped therein. On the other hand, none of the uranous ion, U++++,is completely reduced to the metal state, U, due to the fact that itinherently possesses a high over-voltage.

Further, it will be understood that the rotation of the disks 46 isefiective not only to carry the metal impurities from the body ofelectrolyte 65 into the mercury pool 62 in the manner previouslyexplained, but it also agitates the body of electrolyte 65 and themercury pool 62 in order to facilitate the electrolysis. Finally, theconstant rotation of the disks 46 causes a freshly amalgamated surfacethereof to be presented from the mercury pool 62 to the body ofelectrolyte 65, thereby maintaining substantially constant the internalresistance of the electrolytic cell and consequently the electrolyticcurrent theretbrough. Under the operating conditions specified theelectrolytic cell 10 requires no separate cooling system.

Incident to operation of the electrolytic cell 10, the anion Clmigratesthrough the partition elements 28 to the anode elements 38 disposed inthe anode compartments 30, whereby some C12 gas is liberated and escapesfrom the anode compartments 30 to the atmosphere. Of course some of thischlorine gas is trapped in the electrolyte disposed in the anodecompartment 30; however, substantially none of it migrates through theporous partition elements 28 into the electrolyte disposed in thecathode compartment 31, due to the character of the porous partitionelements 28, the porosity of the partition elements 28 accommodatingconduction of the electrolyte and consequently the electrolytic currenttherethrough, but substantially preventing the migration of the chlorinetherethrough whether in the vapor phase or in solution in theelectrolyte. This arrangement is very advantageous, in view of the factthat the chlorine does not contaminate the electrolyte disposed in thecathode compartments 31, whereby the oxidizing effect of chlorine on theions in the cathode compartments 31 is eliminated. Of course it will beunderstood that chlorine gas possesses a high oxidizing potential and iscapable readily of oxidizing the uranous ion, U++++, back to the uranylion, UO2++, as well as Fe++ back to Fe+++, thereby preventing efficientoperation of the electrolytic cell 10. However, this difiiculty isovercome due to the construction of the partition structure mentioned,whereby the electrolytic cell 10 operates efiiciently substantiallyentirely to reduce the uranyl and ferric ions to the uranous andcompartments 31 in the upper casing section 12 to bedrained therefromand conserved. The body of electrolyte 65 remaining in the anodecompartments 30 in the upper casing section 12 may be drained therefromin any suitable manner and discarded; for example, such electrolyte maybe siphoned out of the anode compartments 30. The conserved electrolyteis then returned to the supply receptacle 111 to be treatedsubsequently, and the mercury is reconditioned in order to eliminate theamalgamated and trapped metal impurities. Also, at this time the othercomponent parts of the electrolytic cell 10 may be cleaned, therebyreconditioning the cell for further use. Thereafter, the required amountof fresh mercury is poured back into the lower casing section 11 throughthe opening formed in the bottom wall 17, in order to form a new mercurypool 62 of the character specified. A quantity of electrolyte, 3N HCl,is poured ino the upper casing section 12 through the open top in orderto form a body of electrolyte 65 as a head on the mercury pool 62 and tofill the anode and cathode compartments 30 and 31, respectively, in themanner previously explained. At this time, the electrolytic cell 10 isconditioned for subsequent operation in the manner previously noted.

It is pointed out that the quantity of chloride solution 126 containedin the storage receptacle 112 which has been treated or reduced in theelectrolytic cell 10 is subsequently subjected to a suitablepurification treatment in order to recover the contained uranium, such,for example, as that disclosed in the previously mentioned copendingapplication of Kamen and De Haan.

The term uranium is employed in the present specifi-- cation in ageneric sense, without reference to whetherit is present in the free orcombined states, unless indi-- cated otherwise by the context.

In view of the foregoing, it will be apparent that there has beenprovided an electrolytic cell of improved construction and arrangement,which is especially adapted for use in conjunction with the reductionand purification of wash solutions derived from calutrons employed inthe calutron method of producing uranium enriched with 2s5 While therehas been described what is at present considered to be the preferredembodiment of the invention, it will be understood that variousmodifications may be made therein and it is intended to cover in theappended claims all such modifications as fall within the true spiritand scope of the invention.

What is claimed is:

1. An electrolytic cell having a casing comprising an upper casingportion removably secured to a lower casing portion, a plurality ofalternately disposed anode and cathode compartments separately enclosedwithin said upper casing portion and adapted respectively to contain afirst body of electrolyte and a second body of circulating electrolytemixed with a solution to be treated, porous partition members separatingadjoining compartments and forming the walls thereof, an anode for eachanode compartment, a movable cathode for each cathode compartment, apool of mercury disposed in the lower portion of said casing and theupper surface thereof contacting said partition members to form aclosure for each of said cathode compartments, means for moving saidcathode thereby to immerse a given portion thereof successively in themercury pool, in the circulating body of electrolyte 111. and imtliemercurypool, means continuously supplying a solution to be treated tothe'cathod'e-compartmentsand means continuously removing treatedsolution from the cathode compartments.

2; A cell as set forth in claim 1 wherein a plurality of said separatelycontained cathode compartments are connected in series By means ofconduits disposed above the pool of mercury.

3. A- cell asset forth in claim 1,v wherein said means 10 for moving thecathode comprises a rotatable shaft immersed in said pool of mercury.

R'eferencesCitedin the tile of this patent UNITED STATES PATENTS

1. AN ELECTROLYTIC CELL HAVING A CASING COMPRISING AN UPPER CASINGPORTION REMOVABLY SECURED TO A LOWER CASING PORTION, A PLURALITY OFALTERNATELY DISPOSED ANODE AND CATHODE COMPARTMENTS SEPARATELY ENCLOSEDWITHIN SAID UPPER CASING PORTION AND ADAPTED RESPECTIVELY TO CONTAIN AFIRST BODY OF ELECTROLYTE AND A SECOND BODY OF CIRCULAING ELECTROLYTEMIXED WITH A SOLUTION TO BE TREATED, POROUS PARTITION MEMBERS SEPARATINGADJOINING COMPARTMENTS AND FORMING THE WALLS THEREOF, AN ANODE FOR EACHANODE COMPARTMENT, A MOVABLE CATHODE FOR EACH CATHODE COMPARTMENT, APOOL OF MERCURY DISPOSED IN THE LOWER PORTION OF SAID CASING AND THEUPPER SURFACE THEREOF CONTACTING SAID PARTITION MEMBERS TO FORM ACLOSURE FOR EACH OF SAID CATHODE COMPARTMENTS, MEANS FOR MOVING SAIDCATHODE THEREBY TO IMMERSE A GIVEN PORTION THEREOF SUCCESSIVELY IN THEMERCURY POOL, IN THE CIRCULATING BODY OF ELECTROLYTE AND IN THE MERCURYPOOL, MEANS CONTINUOUSLY SUPPLYING A SOLUTION TO BE TREATED TO THECATHODE COMPARTMENTS AND MEANS CONTINUOUSLY REMOVING TREATED SOLUTIONFROM THE CATHODE COMPARTMENTS.